For example, a motor type damper device which is an example of a motor actuator is used in a refrigerator. In a refrigerator, cold air which is cooled by a compressor is supplied into a chamber and, when a temperature in the chamber becomes a predetermined value or lower, supply of the cold air is stopped. When the temperature rises, cold air is supplied to the chamber to maintain the temperature in the chamber in a prescribed state. The motor type damper device is disposed in a passage for cold air to regulate supply of the cold air.
A motor type damper device has been conventionally known which includes a motor such as an AC synchronous motor or a stepping motor as a drive source and, in which a baffle disposed in a flow path for cold air is opened or closed by a drive mechanism. For example, the motor type damper device includes a mechanism for causing a baffle to open or close with the use of an AC motor as a drive source and a micro switch for detecting an open position or a closed position of the baffle. In this case, there are two systems, i.e., a self-cutting circuit system (see, for example, Japanese Patent Laid-Open No. 2000-130915) and a signal control system in accordance with a connecting system of the motor with the switch.
In the conventional micro switch system as described above, there are variations of a pushing quantity, force, and/or time interval of a button of the micro switch and variations of an “ON” position and an “OFF” position and, in addition, there is further a variation in assembling accuracy and thus reliability of “ON” or “OFF” signal is not satisfactory. Further, in a contact piece system in which the baffle is opened or closed by using a cam and contact pieces, one of terminals of a motor is covered and insulated by a resin case and thus this system is not capable of being modified to the signal control system.